Propulsion mechanism



Feb. 5; 1924. 1,4823@ H. M. CAKE PROPULS ION MECHANI SM Filed July 6,1918 5] wom/Hofe Patented Feb. 5, 1924.

f NITE!) srA'rs HORACE M. CAKE, 0F PHILADELPHIA, PEN'NSYII'ATANIA.

PBOPULSION Application led July .6, v

To all whom t may concern.

Be it known that I, HORACE M. CAKE, a citizen of the United States,residing at Philadelphia, in the county of Philadelphia and State ofPennsylvania, have invented certain new and useful Improvements inPropulsion Mechanism, of which the following is a specification.

This invention relates broadly to propulsion and more specifically tomechanism for balancing and stabilizing propelling systems.

The principal object of the present invention is a mechanism forpropelling torpedoes, airships, and the like, by rotary screw propellersdriven in such manner as to overcome any tendency of the propelleraction to cause the torpedo, airship, or the like, to rotate on the axisof the propeller.

A still further object of the present invention is a mechanism asspecified wherein the invention is characterized by rotating a pair ofscrew propellers in opposite directions and com ensating the forcesabsorbed by the propel ers in such manner that each propeller at alltimes absorbs one-half of the drivin power.

A still urther object of the present invention isa mechanism asspecified and wherein the forces to be absorbed by the propellers aredelivered through compensating mechanism which transmits the energydirectly to one propeller-and through reversing gearin to the otherpropeller, whereby the propel ers are driven in opposite directionsthrough the compensating devices so thatfvibrations due 'to the passingof propeller blades ongpposingpropellers are not4 ytransmitted directlyto`thedriving shaft but `are absorbed through'thefunctioning ofthecompensating mechanismand'by means of the framework. 'j f p Morelspeciiicallylone .mechanism for carrying outpmy'invention comprisesahead,

ldirectly connected tothedriving or` povv'er shaft, and carryingcompensating. gears.`

One sideof these gears'pis4 directly (':onnectedto al bevel gear onthepropeller shaft for the outer propeller, and theother-iside'"there-lof isconne'cted with1 a bevelfgez'urwhichv transmitsthrough a lcasing toreversing" gears which vdrive a tubular shaft carrying" the innerpropellerpsothatthe 'entire 'sys- 'f tem comprisesa pair of voppfositelyydriveny propellers rotating on a common axis and MECHANISM.

1918. Serial No. 243,523.

receiving power through a differential compensating gearing. Other andfurther objects of the present invention will in part be obvious andwill 1n part be pointed out hereinafter in the specification followingby reference to the accompanying drawings Aforming a part thereof. y

The figure of the drawing is more or less diagrammatic and shows aportion of the construction in section in order to more clearlyillustrate the relation of parts.

In the art of screw propellers it is well recognized there is a tendencyof a single screw propelled ship, torpedo, aeroplane, or

the like, to rotate on the axis of the propeller shaft and oppositel tothe rotation of the propeller itself. This ei'l'ect is partly due toreaction on the propeller blades, partly due to the impossibility ofmaking theoretically true propellers for all conditions of speed, andpartly due to other causes well known in the art. Attempts have vbeenmade to overcome the foregoing difficulties by using twin screwsrotating on independent axes; and also attempts have been made to.eliminate the foregolng diiculties by providin a pair of oppositelyrotated positively riven screws revolving about a common axis. Thelatter mechanism is most commonly employed for propellers for torpedoes.Neither of the proposed constructions completely overcome thedifficulties specified vand in both cases additional vibration isintroduced. In propellers rotating in opposite directions around acommon axis,"vibration is accentuated because each timethe blades on oneropeller pass into the zone of waterdisturbe 'by the blades of the otherpropeller, a different stress conditionis established, and where thepropellers revolve vat high speedthe vibration due 'to ythis conditionlis greatly increased,V

y"and absorbs a large am'ountof tlie driving ener .y "Furthermorebecause of the imposn sibilityy'of ymaking theoretically correctpropellerspas'to pitch,lbalance, etc., it is difi vficultfandvi-npracticfefis substantially impos- "siblefto provide af pair'ofpositivelyvdriven propellers vwhich will not rotate the body of a torpe.v-being driven V.through the water.

nating vibrations due to propeller designs,

io' dolaround its own, axis whenit is i To oveicometlie'diiiiciilties of the-knownk fartaiid to provide aconstruction lfor elimiy. lll() I lsisand water or air disturbances, theinvenvtionA which will morespecifically be described hereinafter, comprises broadl the arran ementof a pair of axially aligned prope 1ers of opposite pitch mounted insuch manner as to receive their driving power through a differentialgearing an reversing gearing so that one-half of the horsepower of thedriving forces rotates one screw propeller in one direction and theother half of the driving power rotates the other screw propeller in theopposite direction. By this construction it will be noted that when anyunbalanced condition exists as to one propeller the surplus forceproducing the unbalanced condition is transmitted immediately throughthe differentialgearing to the other propeller so that at all timesthere is true compensation between the propellers without transmittingthe compensatory forces or stresses to the drivin shaft. This fact tendsto relieve the driving shaft of forces which otherwisewould causeundesirable vibration. It will also be noted 4that by this constructionif there is a tendency of the torque of either propeller to preponderateover the other propeller in such manner as would cause'a torpedo, or thelike, to rotate on its own axis where the propeller is positively drivenwithout reciprocal action, such preponderance is immediatel. absorbed bybeing distributed between t e propellers. Therefore there is no turningelement or function which tends to rotate the boat, torpedo, airship, orthe like, around the axis of the propeller shaft, where this invention`is used.

Referring now more particularly to the drawings the drive shaft 1carries a transmission head 2 on which is mounted a pair of compensatinggears 3. The compensatingx gears on one side engage a bevel gear 4 t atis integral with a collar 5 that is free lto rotate around the driveshaft 1. This J collar 5 carrying the bevel ear 4 is secured to ahousing 6, b means o machine screws or the like. This housing terminatesin a reversing bevel gear 7 which engages one side of a pair of idlergears 8 mounted to rotate on stubshafts 9 that are anchored in thestationary member 10 which is secured to a part of the frame work 11 ofthe torpedo, ship, or 'other construction, carrying this propellingmechanism. The compensatin gears 3 are also in engagement with a bevegear 12v which is secured to a propeller shaft 13. The idler gears 8also engage a bevel ar 14 which is mounted on a tubular prope er shaft15 adapted to rotate about the propeller shaft 13. The tubular propellershaft 15 carries a propeller 16 having its blades pitched in onedirection and the propeller shaft 13 carries a ropeller 17 having itsblades pitched in t e opposite direction.

It is obvious from the foregoing that power from the driving shaft 1will` be transmittedy equally to the propellers ,16 and 17 one half ofthe power going to each propel er. In view of this fact it is alsoobvious that the resistance on these propellers tends to be equal'at alltimes. Now since the pitch of the blades on propeller 16 is opposite toIthe pitch of the blades on propeller 17, and since the propellers rotatein opposite directions it follows the driving reactions on thepropellers are equal and opposite so that the system is rotativelybalanced on the axis around which the ropellers revolve. Furthermoresince the alancing of the otherwise unequal conditions is, accomplishedby energy transference from one propeller to the other, the main drivingshaft is relieved from stresses that would otherwise dissipate a portionof the driving energy. This results in a balanced cushioning actionwhich renders the reaction-against the main driving shaft smooth andeven and is a further reason for obviating shocks and vibrations aspreviously specified. i A

It is obvious that the specific constructions herein disclosed. ma bevaried somewhat without departing rom my invention and therefore Idesire that it shall be understood that the disclosure herewith is i1-lustrative and not to be taken in the limitin sense.

aving thus described my invention what I claim is:

1. In a propulsion mechanism in combination, a drivin shaft, atransmission head carried on sai driving shaft, compensating gears uponsaid transmission head, a face plate carrying thereon a beveled gear inengagement with the compensating gears a tubular shaft, a propeller onsaid tubu ar shaft, a casing secured to said face plate. reversinggearing operatively connecting said casing and said tubular shaft, acylindrical shaft mounted within said tubular shaft, a propellercarriedupon said cylindrical shaft, and a beveled. gear on the cylindricalshaft and in engagement with the compensating gears; the driving shaft,the

tubular shaft, and the cylindrical shaft, all y v being in axialalignment.

2. In a propulsion mechanism in comblnation, a driving shaft, atransmission head, compensating gears carried by said transmission head,a cylindrical shaft, al tubular. driven shaft, operative meansconnecting said tubular shaft with said compensating gears, saidoperative means includin versinggearing connecting said cylin ricalshaft with said compensating gears to drive IIS said cylindrical shaftin the opposite rotay tive direction to which said tubular shaft isdriven, a propeller carried upon said tubular shaft and a propellercarried upon said cy`- lindrical shaft; the driving shaft, the tubi1-lar shaft and the cylindricali driven shaft all i being in axialalinement.

3. In a propulsion mechanism in combination, a driving shaft, atransmissiony head carried by said driving shaft, compensating gearscarried on the transmission head, beveled gears engaging saidcompensating gears on d1ametrical y opposite sides, a tubular shaft, apropeller on said tubular shaft, reversinggearlng, a cylindrical shaftmounted Within said tubular shaft, apropeller carried on saidcylindrical shaft, one 'of said beveled gears being operativelyconnected with said tubular shaft through said reversing gearing, andthe other of said beveled gears being operatively connected With saidcylindrical shaft; the driving shaft,

the tubular shaft and the driven cylindrical shaft all being axiallyalined.

4. In a propulsion mechanism in combination, .a driving shaft, twodriven shafts. screw propellers carried on said driven shafts, reversinggearing, and com ensating means operatively connecting sai driving shaftwith one of said driven shafts independently of said reversing gearingand op eratively connecting said driving shaft through said reversinggearing to the other driven shaft to drive the driven shafts in oppositedirections, the blades of the screw propellers being pitched in oppositedirections; the drivlng shaft and both driven shafts being in axialalinement.

HORACE M.y CAKE.

